RHEL/CentOS softraid

1: create softraid volume
2: raid assignment
grub> device (hd0) /dev/sda

grub> device (hd1) /dev/sdb
grub> root (hd0,0)
grub> setup (hd0)
grub> root (hd1,0)
grub> setup (hd1)
grub> quit